1. Field of the Invention
The present invention relates to an image-taking apparatus using an image-pickup element such as a video camera or a digital camera.
2. Description of the Related Art
An image-taking apparatus such as a video camera or a digital still camera has an image-taking lens system and an image-pickup element used therein. There are many cases, however, where an optical axis of the image-taking lens system is slightly displaced from a center of the image-pickup element due to a manufacturing error and the like.
In general, a light amount is reduced as it gets away from an optical axis on an image surface. Therefore, if the center of the image-pickup element is displaced from the optical axis of the image-taking lens system, there arises unbalance as to the light amount of four peripheral parts (in the vicinity of four corner parts) on the image-pickup element.
In the case of using an image-taking lens capable of variation of magnification, if the center of the image-pickup element is slightly displaced from the optical axis of the image-taking lens system, there occurs a phenomenon of so-called “zoom center displacement” in which an object image-formed at the center of the image-pickup element shifts due to the variation of magnification.
And as the image-pickup element becomes higher-pixelated and miniaturized in recent years, the slight displacement of the center of the image-pickup element from the optical axis of the image-taking lens system significantly influences a quality of a taken image.
Japanese Patent Laid-Open No. 2000-134528 discloses a method which resolves the displacement of the image-pickup element from the optical axis of the image-taking lens system by adjusting a position of the image-pickup element.
In the case of the adjustment method disclosed in Japanese Patent Laid-Open No. 2000-134528, however, the entire image-pickup element unit including a substrate which drives the image-pickup element must be moved in reality. Therefore, it is necessary to provide a space to move the image-pickup element unit in the image-taking apparatus, and so there is a problem that the image-taking apparatus becomes larger-size.
In addition, the image-pickup element is fixed (attached) on the image-taking lens system by adjusting its position, and so positioning work is cumbersome.